The pre-occular tear film makes an important contribution to the normal physiology of the eye and its dysfunction is implicated in a number of increasingly important opthamological disorders. We have studied the biophysical properties of the lipid component of the tear film that are important to its function by spreading the lipids in a thin layer on a water surface, and using optical methods to investigate molecular organisation and dynamic behaviour. This work has provided important insights on the behaviour of the natural tear film and on artificial mixtures proposed for therapeutic use. The new research will characterise abnormal tear film samples (such as in the dry eye syndrome), where the stability and functional performance of the tear film is compromised. This work will help us understand the molecular bases of disease, and possibly offer routes for ameliorating tear film function.